This invention concerns a method to reduce the access time for rotating storage media with variable angular velocity by displacement of existing kinetic energy, while at the same time the energy consumption is being reduced. The access time for rotating storage media is based on a radial displacement of the reading head and a pending of the correct position of the rotating disc (turning). In order to put a maximum amount of information on a circular, rotating disc surface, some storage media have been constructed according to the CLV (Constant Linear Velocity) method, i.e., the disc is read at a constant velocity along the track, thus constantly changing its angular velocity at recording or reading at different radial distances. Disc storage media with a partition in sectors could have the number of sectors as a step by step function of the radius.
The invention could for example be used on discs of the Compact Disc type, which under continuous reading constantly change their angular velocity by keeping a constant reading speed along the information track. For applications of Compact Discs on computers, so-called CD-ROM, the angular velocity of the disc must in a short time and frequently be altered at each reading, as the information normally is scattered on different locations and thus at different radii on the disc.
Certain sectorized storage media with an extended number of sectors with a extended number of radii also require a change of the angular speed at recording or reading at different radii. Normally a relatively large quantity of energy and a powerful driver unit are required in order to alter the angular velocity in a short time.
The cost for this is traditionally relatively high. Forces of actions and reactions often cause vibrations and thus interferences easily may arise when reading.